﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Exercise5
{
    internal class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("请输入学生成绩：");
            int score = Convert.ToInt32(Console.ReadLine());

            if (score >= 90)
            {
                Console.WriteLine("成绩等级：A");
            }
            else if (score >= 60 && score <= 89)
            {
                Console.WriteLine("成绩等级：B");
            }
            else
            {
                Console.WriteLine("成绩等级：C");
            }

            Console.ReadLine();
        }
    }
}
